/Engine/Plugins/Runtime/GeoReferencing/Source/GeoReferencing/Public/GeoReferencingSystem.h
Get the East North Up vectors at a specific location - Not in engine frame, but in pure ECEF Frame !
void GetECEFENUVectorsAtECEFLocation ( const FVector & ECEFCoordinates, FVector & ECEFEast, FVector & ECEFNorth, FVector & ECEFUp )